The present invention relates to method and apparatus for aiming a spray etcher nozzle and, more particularly, to using a source of illumination at the spray nozzle tip to illuminate the wafer surface so as to assist in properly aiming the nozzle with respect to the wafer.
In the fabrication of semiconductor devices, for example, microelectronic or optoelectronic devices, there may be certain processes that require the use of a etch material sprayed on the surface of a wafer containing the optoelectronic devices. For example, GaAs or InP wafers are often etched, one at a time, in a spray chamber. The wafer may be etched in, for example, a dilute acidic or basic solution, rinsed on both sides, then transported out of the spray chamber. The etchant solution is delivered to the chamber via suitable tubing (e.g., Teflon) from an external source. The solution exits a nozzle located in a ball mount, where the mount is fully adjustable to allow for positioning of the spray nozzle tip by the user.
Although the use of the fully adjustable nozzle tip permits a great deal of freedom in setting up the tool, the "aim" of the nozzle with respect to the wafer has been found to affect the intra-wafer etch uniformity. That is, various optoelectronic devices on the same wafer may exhibit different etch geometries. In current systems, the position of the spray with respect to the wafer surface is usually "eyeballed" by the machine operator and, therefore, may often be not positioned in the optimum location required to provide uniform results.
Thus, a need remains in the art for a means of adjusting the aim of spray etcher nozzles.